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Unformatted text preview: stat 226 Homework 6 due tues, April 17th in class Show all your work for full credit and print any necessary JMP output! 1. A study compares two groups of mothers with young children who were on welfare two years ago. One group attended a voluntary training program offered free of charge at a local vocational school and advertised in the local new media. The other group did not choose to attend the training program. The study finds a significant difference ( p-value < . 01) between the proportions of the mothers in the two groups who are still on welfare. The report says that with 95% confidence the percent of the non attending group still on welfare is 21% ± 4% higher than that of the group who attended the program. You are on the staff of a member of Congress who is interested in the plight of welfare mothers and who asks you about the report. (a) Explain briefly and clearly what “a significant difference ( p-value < . 01)” means. (b) Explain briefly and clearly what “95% confidence” means. (c) Is this study good evidence that requiring job training of all welfare mothers would greatly reduce the percent who remain on welfare for several years? Why or why not? 2. A Local television station announces a question for a call-in opinion poll on the six o’clock news and then gives the response on the eleven o’clock news. Today’s question concerns a proposed increase in funds for student loans. Of the 2372 calls received, 1921 oppose the increase. The station, following standard statistical practice, makes a confidence statement: “81% of the channel 13 Pulse Poll sample oppose the increase. We can be 95% confident that the proportion of all viewers who oppose the increase is within 1.6% of the sample result.” Is the station’s conclusion justified? Explain your answer.of the sample result....
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This note was uploaded on 05/05/2010 for the course STAT 226 taught by Professor Abbey during the Fall '08 term at Iowa State.
- Fall '08